Spray drying conditions and encapsulating composition effects on formation and properties of sodium diclofenac microparticles

This paper reports the preparation and characterization of sustained release sodium diclofenac microparticles by spray drying. Aqueous dispersions of ethyl cellulose (Surelease®) and Eudragit RS 30 D® were evaluated as controlled release polymers. The product properties (product moisture, size distribution, particle morphology, flow properties, total drug load, in-vitro dissolution studies, and encapsulating efficiency) were determined as a function of inlet temperature of the spray drying, the feed flow rate and composition of the microencapsulating formulation. In general, lower values of the product moisture content were observed at higher drying temperatures. The spray-dried product was composed mainly by rounded-shape and multi-size particles. The mean particle diameters of the Eudragit based microparticles tended to be slight bigger than the Surelease based microparticles. The spray dried microparticles showed delayed drug dissolution rates, sustaining the drug release for several hours. These findings confirm the feasibility of the spray drying for preparation of microparticles with sustained release properties. The physical and chemical properties of the microparticles can be changed by varying the spray drying parameters as well as the microencapsulating formulation.     

The assembly line worker assignment and balancing problem with stochastic worker availability

Assembly lines can be employed successfully in sheltered work centres to better include persons with disabilities in the labour market as well as to improve production efficiency. The optimal assignment of a heterogeneous workforce is known as the assembly line worker assignment and balancing problem (ALWABP). These assembly lines are characterised not only by a heterogeneous workforce, but also by high levels of absenteeism, which makes it more difficult to obtain stable and efficient line balancing solutions. In this paper, an extension of the ALWABP to minimise the expected cycle time under uncertain worker availability is proposed. We model this problem as a two-stage mixed integer program, and propose local search heuristics for solving it. Computational experiments show that stochastic modelling can help to improve the line’s efficiency and that the proposed heuristics produce good results for instances of practical size.     

A novel application of mesoporous silica material for extraction of pesticides

The mesoporous silica material MCM-41 was prepared by the sol-gel method and characterized using X-ray diffraction (XRD), N₂ adsorption-desorption and thermogravimetric analysis. The material was tested for extraction of trichlorfon, pyrimethanil, tetraconazole, thiabendazole, imazalil and tebuconazole from mango fruit, with analysis using gas chromatography-mass spectrometry (GC/MS). In experiments carried out in triplicate, at a 1.0 mg/kg concentration level, recoveries using the MCM-41 sorbent were in the range 73-103%. Comparison of MCM-41 with commercially available silica gel showed that MCM-41 was a similar extracting phase for the pesticides investigated with a significant cost advantage over this conventional material.     

Volatile Constituents of Jambolan (<Emphasis Type="Italic">Syzygium cumini</Emphasis> L.) Fruits at Three Maturation Stages and Optimization of HS-SPME GC-MS Method Using a Central Composite Design

The volatile compounds of jambolan (Syzygium cumini L.) fruit were determined at three different maturity stages (unripe, half-ripe, and ripe) by headspace solid-phase microextraction (HS-SPME)–gas chromatography-mass spectrometry (GC-MS) technique using five different fibers (Fused silica PDMS/DVB, DVB/CAR/PDMS, PEG, Stable flex PDMS/DVB, and PDMS). The optimal extraction conditions were evaluated using different variables such as adsorption temperature (minimum 25 °C, maximum 55 °C), salt quantity (minimum 0, maximum 30.0%), and extraction time (min 10, max 30 min). The major classes of compounds identified were ester, terpene, alcohol, aldehyde, and carboxylic acid. Ninety volatile compounds with characteristics aroma attributes were identified, and the primary compounds linked with development of characteristics aroma of ripe jambolan fruit pulp were trans-β-ocimene, β-ocimene, caryophyllene, humulene, D-α-pinene, L-β-pinene, β-pinene, D-limonene, α-terpineol, neo-allo-ocimene, 2-hexenal (E), δ-cadinene, 3-hexen-1-ol, (Z) β-linalool, terpinolene, eremophilene, valencene, 1-hexanol, longipinene, γ-terpinene, γ-muurolene, endo-borneol, o-cymene, nonanal, terpinen-4-ol, β-terpineol, α-muurolene, fenchol, α-fenchene, β-thujene, benzaldehyde, (E)-2-hexenal, β-cadinene, and decanal.     

Structural and optical properties of pillared Eu3+-containing layered double hydroxides intercalated by 2- to 12-carbon aliphatic dicarboxylates

While the versatile composition of layered double hydroxides(LDHs)allows the introduction of almost any polyvalent cation in their structure,the exchangeable negatively charged ions intercalated between the plates increase their vast range of functionalities.Here we report on the preparation and optical properties of pillared Eu³⁺-substituted ZnAl LDHs intercalated by aliphatic dicarboxylates:-OOC-(CH₂)_n-2-COO-.The basal distance in these materials is dependent on the size and packing of the intercalated anions.By varying the number(n)of carbon atoms in the aliphatic chain from 2 to 12,the interlayer gallery of these ZnAlEu LDHs is considerably expanded from 0.9 to 2.1 nm.In the interlayer gallery,the aliphatic dicarboxylates form a monolayer,with the aliphatic chain inclined by an angleα≈63°with the hydroxide layers.The carbon atom in the COO-group is 0.43 nm far from the metal plane,showing that these carboxylates are not grafted in the brucite-like layers.These LDHs are thermally stable up to around 150℃,after which dehydroxylation of the hydroxide layers is observed.The Judd-Ofelt intensity parameters were obtained and compared to the Eu³⁺-containing complexes with the same ligand series indicating a more symmetrical and less polarizable chemical environment around the rare earth ion.     

Analysis of operating system diversity for intrusion tolerance

One of the key benefits of using intrusion‐tolerant systems is the possibility of ensuring correct behavior in the presence of attacks and intrusions. These security gains are directly dependent on the components exhibiting failure diversity. To what extent failure diversity is observed in practical deployment depends on how diverse are the components that constitute the system. In this paper, we present a study with operating system's (OS's) vulnerability data from the NIST National Vulnerability Database (NVD). We have analyzed the vulnerabilities of 11 different OSs over a period of 18 years, to check how many of these vulnerabilities occur in more than one OS. We found this number to be low for several combinations of OSs. Hence, although there are a few caveats on the use of NVD data to support definitive conclusions, our analysis shows that by selecting appropriate OSs, one can preclude (or reduce substantially) common vulnerabilities from occurring in the replicas of the intrusion‐tolerant system. Copyright © 2013 John Wiley & Sons, Ltd.     

Sharing Memory between Byzantine Processes Using Policy-Enforced Tuple Spaces

Despite the large amount of Byzantine fault-tolerant algorithms for message-passing systems designed through the years, only recently algorithms for the coordination of processes subject to Byzantine failures using shared memory have appeared. This paper presents a new computing model in which shared memory objects are protected by fine-grained access policies, and a new shared memory object, the Policy-Enforced Augmented Tuple Space (PEATS). We show the benefits of this model by providing simple and efficient consensus algorithms. These algorithms are much simpler and requires less shared memory operations, using also less memory bits than previous algorithms based on ACLs and sticky bits. We also prove that PEATS objects are universal, i.e., that they can be used to implement any other shared memory object, and present lock-free and wait-free universal constructions.     

Preparation of Al2O3 and MgAl2O4-based samples with tailored macroporous structures

In this work we successfully obtained freeze-cast alumina (Al₂O₃) and magnesium aluminate spinel (MgAl₂O₄) samples. Camphene was used as the freezing vehicle in this study. The specimens prepared herein were examined by Archimedes tests, scanning electron microscopy, and X-ray powder diffraction. Cold crushing tests were also carried out at room temperature. It was observed that the pore structure of Al₂O₃ samples can be tailored by changing the solid loading and freezing rate; the higher the solid loading and freezing rate, the finer the pore structure of the freeze-cast sample. MgAl₂O₄-based specimens were fabricated by keeping the solid loading in the starting slurry at 30 vol% and using liquid nitrogen as the cooling agent. The material obtained from a 60 Al₂O₃?40 MgO slurry showed a spinel amount of about 90%, an expressive total porosity (63 ± 3%), and a significant cold crushing strength (58 ± 6 MPa). In addition, this material exhibited the finest pore structure among the composition studied herein, showing a mean pore size of about 4 µm.     

Photoelectrochemical hydrogen generation at hybrid rGO-Sn3O4/SnO2 nanocomposite

Journal of Applied Electrochemistry - This study investigates the photoelectrocatalytic water splitting at Sn3O4 and ternary rGO-Sn3O4/SnO2 heterostructure nanocomposite materials. The...     

A note to: A multiple-rule based constructive randomized search algorithm for solving assembly line worker assignment and balancing problem

Journal of Intelligent Manufacturing - Some of the solutions reported in a recent paper (Akyol and Baykasoglu in J Intell Manuf 30(2):557–573, 2019. https://doi.org/10.1007/s10845-016-1262-6...